Metabolic Healthy Obesity (MHO) is a type of obesity where, despite excess fat, the patient has normal blood tests. What is metabolically healthy obesity? Can obesity be healthy?
Obesity is a chronic disease, the symptom of which is excess fat.
In people with obesity, excessive body weight increases the risk of serious diseases such as myocardial infarction, ischemic stroke, hypertension, type 2 diabetes, or cancer. But is it for everyone? Information about the fact that obesity can be healthy caused a storm in the medical environment. However, is healthy obesity really there?
The concept of Metabolic Healthy Obesity (MHO) appears quite often in the scientific literature.
Although the very idea of MHO was created in the 1980s, however, neither the definition nor the criteria for the diagnosis of this type of obesity have yet been established. It is known that people with MHO, despite a BMI over 30 kg / m2, have no abnormal blood test results such as too high glucose, insulin or lipid profile, or are slightly above normal. Hence, the conclusion is that excess fat seems not to interfere with metabolic activities in people with MHO and theoretically does not affect the risk of developing diseases that are complications of obesity.
Research shows that up to 1/3 of Americans can be qualified as people with MHO.
However, the lack of a precise definition and the use of various qualification criteria by researchers in research makes it difficult to assess this phenomenon. Therefore, depending on the studied population, in the group of obese people, the incidence of MHO ranges from 10% to 76%. Preliminary epidemiological data indicate that MHO is more common in women than in men, but the older the patients are (both sexes), the less frequent MHO.
The causes of MHO formation are still unclear.
However, there were several scientific hypotheses explaining metabolic differences in people with obesity. Currently, the hypothesis of chronic inflammation is the leading one . Studies show that people with MHO have a significantly lower level of markers of inflammation, such as C-reactive protein (CRP), whose high blood level is characteristic of people with metabolic unhealthy obesity. This hypothesis assumes that long-lasting, chronic inflammation is ou of people with MHO at a very low level without causing metabolic disorders.
Another reason for metabolic differences in the group of people with obesity may be the distribution and type of adipose tissue. It is well known that visceral, or visceral, tissue that accumulates around internal organs has a very high disease potential. And its content in the body correlates with the increased risk of diseases associated with obesity. Perhaps it is the small amount of the inconspicuous tissue that occurs in people with MHO who are responsible for the lack of deviations in metabolic parameters.
Some scientists also explain the significant metabolic differences in people with obesity in the occurrence of genetic polymorphisms associated with the metabolism of adipose tissue, e.g. genes encoding peroxisome proliferator-activated receptors (PPARs).
Recent clinical trials show that despite seemingly unpaired metabolic parameters, people with MHO have an increased risk of developing diseases classified as obesity-related complications. This thesis is confirmed by the latest meta-analyzes of literature data, which showed that people with MHO have an increased risk of cardiovascular diseases (circulatory system) in comparison with people with normal body mass.
In the case of type 2 diabetes, the studies are more divergent.
However, a meta-analysis of literature data from 2014 showed that adults with MHO are more than 4 times more likely to develop type 2 diabetes than people with normal body weight. However, despite this, the risk was half as high as in people with metabolic unhealthy obesity. In the case of other diseases related to obesity, clinical trials that clearly assess the risk of their occurrence in people with MHO are still needed.
Most scientists agree that people with MHO should be treated to reduce weight, despite the fact that people with MHO appear to be metabolically healthy. Some of them even believe that the term MHO should be discontinued and replaced with the term prema-biline syndrome, because it is highly likely that MHO is a temporary state before the appearance of this syndrome. It is emphasized that in one moment the person may be MHO, and over time its condition may change, because excessive body weight is a factor contributing to the development of diseases, and pathological changes can appear in any other time. Some studies have shown that up to 30-40% of people with MHO change their metabolic status to unhealthy within a few years.
In this context, it is also worth mentioning the so-called Metabolic obesity with normal body weight (MONW).
However, as in the case of MHO, its definition and recognition criteria have not been precisely determined. Individuals with MONW, despite the normal BMI values, are characterized by the metabolic profile characteristic of a person suffering from obesity, ie they have increased blood glucose, an abnormal lipid profile, hypertension and insulin resistance. In addition, people with MONW are several times more likely to experience the same diseases as people with obesity. This fact emphasizes even more how complex disease is obesity and complications connected with it.
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